Elliptical L-section R.C. beams - A parametric study using ETABS.

The aim of this research work is to study the most important parameters that affect the loading capacity and behavior of elliptical ring reinforced concrete beams with (L) section. Twenty specimens were modelled using ETABS Software to study the effect of changing the length of the major axis (while keeping the ratio of the major to minor axis equal to 0.64), width, height, thickness, and loading type. The maximum values of negative bending and torsional moments in addition to midspan deflection increase by 1.24-8.24%, 1.33-11.43%, and 32.5-131%, respectively when the major axis of beam increases by 20-60%. Whereas, major axis increase leads to decrease the maximum positive bending moments and load capacity by 5.91-4.45% and 26.5-52.9%, respectively. That happens due to the extending of span length that happened because of major axis increase. When the beam height increases by 25-75%, the maximum positive and negative bending moments (M+ve) and (M-ve), torsional moments and load capacity increase by 33.92-102.4%, 33.92-100%, 29.84-89.74% and 38.8-116.6%, respectively. While this increase in height leads to maximum deflection decrease by 5-8.4%. That happens because the beam sectional area increases due to increasing beam height. M+ve and M-ve, load capacity and midspan deflection decrease by 0.33-7.9%, 1.61-1.1%, 4-20%, and 11-30%, respectively when beam width increases by 46.6-140%. While this increase in width leads to torsional moment to increase by 2.15-0.87%. The sectional area of beam increases because of width increase, i.e., additional strength capacity. When thickness of beam increases by 100-500%, M+ve, M-ve, load capacity and maximum deflection decrease by 4.25-18.8%, 2.3-16.2%, 7.4-37% and 19.8-67%, respectively, whereas the torsional moments increase by 1.42-0.12%. Finally, torsional moments increase by 0.68-1.49 %, respectively due to testing through partial or full uniform load by 20-100% length of span. [ABSTRACT FROM AUTHOR]